// SPDX-License-Identifier: GPL-2.0#include "comm.h"#include <errno.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <linux/refcount.h>#include <linux/rbtree.h>#include <linux/zalloc.h>#include "rwsem.h" struct comm_str {	char *str;	struct rb_node rb_node;	refcount_t refcnt;}; /* Should perhaps be moved to struct machine */static struct rb_root comm_str_root;static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,}; static struct comm_str *comm_str__get(struct comm_str *cs){	if (cs && refcount_inc_not_zero(&cs->refcnt))		return cs; 	return NULL;} static void comm_str__put(struct comm_str *cs){	if (cs && refcount_dec_and_test(&cs->refcnt)) {		down_write(&comm_str_lock);		rb_erase(&cs->rb_node, &comm_str_root);		up_write(&comm_str_lock);		zfree(&cs->str);		free(cs);	}} static struct comm_str *comm_str__alloc(const char *str){	struct comm_str *cs; 	cs = zalloc(sizeof(*cs));	if (!cs)		return NULL; 	cs->str = strdup(str);	if (!cs->str) {		free(cs);		return NULL;	} 	refcount_set(&cs->refcnt, 1); 	return cs;} staticstruct comm_str *__comm_str__findnew(const char *str, struct rb_root *root){	struct rb_node **p = &root->rb_node;	struct rb_node *parent = NULL;	struct comm_str *iter, *new;	int cmp; 	while (*p != NULL) {		parent = *p;		iter = rb_entry(parent, struct comm_str, rb_node); 		/*		 * If we race with comm_str__put, iter->refcnt is 0		 * and it will be removed within comm_str__put call		 * shortly, ignore it in this search.		 */		cmp = strcmp(str, iter->str);		if (!cmp && comm_str__get(iter))			return iter; 		if (cmp < 0)			p = &(*p)->rb_left;		else			p = &(*p)->rb_right;	} 	new = comm_str__alloc(str);	if (!new)		return NULL; 	rb_link_node(&new->rb_node, parent, p);	rb_insert_color(&new->rb_node, root); 	return new;} static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root){	struct comm_str *cs; 	down_write(&comm_str_lock);	cs = __comm_str__findnew(str, root);	up_write(&comm_str_lock); 	return cs;} struct comm *comm__new(const char *str, u64 timestamp, bool exec){	struct comm *comm = zalloc(sizeof(*comm)); 	if (!comm)		return NULL; 	comm->start = timestamp;	comm->exec = exec; 	comm->comm_str = comm_str__findnew(str, &comm_str_root);	if (!comm->comm_str) {		free(comm);		return NULL;	} 	return comm;} int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec){	struct comm_str *new, *old = comm->comm_str; 	new = comm_str__findnew(str, &comm_str_root);	if (!new)		return -ENOMEM; 	comm_str__put(old);	comm->comm_str = new;	comm->start = timestamp;	if (exec)		comm->exec = true; 	return 0;} void comm__free(struct comm *comm){	comm_str__put(comm->comm_str);	free(comm);} const char *comm__str(const struct comm *comm){	return comm->comm_str->str;}